Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
The proximity sensor device can be used to enable control of an associated electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems, including: notebook computers and desktop computers. Proximity sensor devices are also often used in smaller systems, including: handheld systems such as personal digital assistants (PDAs), remote controls, and communication systems such as wireless telephones and text messaging systems. Increasingly, proximity sensor devices are used in media systems, such as CD, DVD, MP3, video or other media recorders or players. The proximity sensor device can be integral or peripheral to the computing system with which it interacts.
Presently known proximity sensors have the ability to detect and determine force applied to a surface of the sensor, for example, by providing one or more force sensors coupled to the surface of the sensor, such as strain gauge load cells, piezoelectric crystal force transducers, and the like. It is also known to estimate applied force by measuring the increased capacitance resulting from the increased contact area when a finger is pressed against the surface. Drawbacks associated with estimating applied force using these techniques include limited accuracy and complex construction. Consequently, such sensors have are limited in their ability to use such determined force as a basis for determining user input. This limits the flexibility of the proximity sensor device to function as an input device. Thus, there exists a need for improvements in proximity sensor devices, and in particular, in the ability of proximity sensor devices to determine and respond to indications of applied force.
Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.